Thermostat



(NoModeL) 1 E. R. WILDER 82: J. P. CLARK.

THERMOSTATQ No. 308,120. Patented N0v.- 18, 1884.

Witnss e-s' Inventors UNITED STATES PATENT OFFICE.

EDMUND R. \VILDER AND JOSIAH P. CLARK, OF PORTLAND, MAINE.

TH ERMOSTAT.

SPECIFICATION forming part of Letters Patent No. 308,120, dated November 18, 1884.

Application filed May 27,1884. (No model.)

To all whom it may concern Be it known that we, EDMUND R. WVILDER and JosIArI P. CLARK, both of Portland, in the county of Cumberland and State of Maine, have invented certain new and useful Improvements in Thermostats; and we do hereby declare that the following is a full, clear, and exact description of the invention, that will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming a part of this specification, in which- Figure 1 is a top plan; Fig. 2, a vertical cross-section through the line y y of Fig. 1, and Fig. 3 a view from the under side.

Our invention relates to thermostats or heatdetectors to be used in connection with firealarms and for kindred purposes.

It consists of a concaved diaphragm of metal inclosed within unyielding walls of some nonconducting substance, one pole of an electric battery being constantly in connection with the diaphragm, while the wire of the other pole is so located with reference to the diaphragm that expansion of the diaphragm will cause the convex side of the same to come into connection with such other pole.

The various parts of this invention may be arranged and used in various ways.

I The following is a description of a device in which the parts may be embodied and used. I) is a circular piece of non-conducting material having ears and the central annular projection, m 00, which may be provided on the outside with screw-threads. Upon this projection may be screwed or otherwise fastened the ring 0, (see Fig. 2,) the diaphragmt' of this metal being firmly held between the projection 00 and the ring 0, as shown in Fig. 2. The convexity of the diaphragm should be toward the piece I), and one side of it should be in continual contact with the wire f, which extends upward from the diaphragm through the projection ac to the stud or screw (1, which is inserted into one of the ears of the piece I). A similar stud or screw is located in the opposite ear, and connected by wire f with the metal plate 9, which is placed above the cen ter of the piece b. The wires f f and plate as well as the head of the screw 71, (of metal,) are covered by the piece or bar 0, Figs, 1 and 2. The screw h passes downward to a point slightly above the diaphragm t. The wires and connections of all the metal parts are thus covered and protected from contact with dirt, water, 850. It is not intended that the diaphragm, the ring a, plate I), and bar a shall be so closely united as to form between these parts an air-tight space. This may be further guarded against by use of a slight air-vent through the ring or plate I).

The purpose of the invention being to indicate when a substance, apartment, or locality has reached a certain degree of heat, the screw it is so set that the curvature or expansion of the diaphragm corresponding to such degree of heat will bring it in contact with the screw 71. By this means, when the apartment, 850., has reached the degree of heat in question, the circuit will be closed, the wire from the positive pole of the battery (for example) being connected with the screw (1, and the wire from the negative pole with the screw d, and the requisite alarm given or registered.

This thermostat is not dependent for its op eration upon the expansion of a confined body of gas or fluid, whereby motion of the diaphragm is obtained. The diaphragm is expandedand its concavity increased by the direct action of'the increased temperature of the surrounding air, and the use of a confined body of air or fluid is not necessary nor conteniplated.

\Vhat we claim as our invention is- 1. An automatic thermostat for the purpose of giving an alarm when a certain degree of temperature is reached, consisting of a concave metallic diaphragm rigidly and closely surrounded by a non-conducting substance, and the conducting-wire f and the adjustable screw or pin 71, having electrical connections, whereby the direct action of the surrounding atmosphere at a certain degree of temperature will, by expanding the diaphragm, establish an electrical circuit through said wire and pin, substantially as described. l

2. In a thermostat, the combination of the concave metallic diaphragm i, operated directly by an increase in the degree of heat of the surrounding atmosphere, and without the interposition of a confined body of air or fluid, said diaphragm being rigidly surrounded by ICO a ring of non-conducting material, the wire f, 4. The combination, in a thermostat, of the the adjustable pin or screw it, and wiref, subdiaphragm *0, plate I), ring 0, bar a, wires f f,

stantially as described. plate 9, pin h, and screws (2 d, substantially I 5 3. The combination, in a thermostat, of the as described, for the purposes set forth. 5 concave. metallic diaphragm i, operated di In testimony that we claim the foregoing We rectly by an increase in the degree of heat of have hereunto set our hands this 15th day of the surrounding atmosphere, and without the May, 1884.

interposition of a confined body of air or fluid, EDMUND R. XVILDER. Said diaphragm being rigidly surrounded by JOSIAH P. CLARK. IO the ring a, of non conducting material, the plate lVitnesses:

I), the wires f f, and screw 71 substantially as J. C. CLAY, described. G. E. BIRD. 

